Understanding SMS character limits

Last updated: January 6, 2026

SMS messages have character limits that determine whether your message will send as a single SMS or be split into multiple segments.

Character Limits for SMS Segmentation

For messages without special characters:

  • Single SMS: Up to 160 characters

  • 10DLC - two SMS segments: Up to 306 characters

  • Toll-free - two SMS segments: up to 302 characters

The second segment limit isn't simply double the first because mobile networks add hidden characters to keep multi-part messages together on the receiving device. This reduces the available character count for subsequent segments.

Note that an SMS message with an emoji only has 70 available characters.

When Messages Become MMS

Your message will send as MMS (not SMS) if:

  • It contains Media attachments (images, GIFs, videos)

  • It is over the SMS character limit (factoring in the increased "cost" of special characters or formatting)

  • A multi segment SMS would be more expensive than an MMS (for example, for short code sending numbers)

Checking Your Message Segmentation

To confirm how your broadcast will send:

  1. Open your broadcast

  2. Look at the preview showing SMS/MMS status